1. Field of the Invention
This invention relates to a novel process for producing 6-acyl-7-deacetylforskolin derivatives expectedly useful as medical drugs.
2. Description of Prior Arts
As process for producing 6-acyl -7-deacetylforskolin, a process which comprises reacting 7-acyl-7-deacetylforskolin with sodium hydroxide in a protonic solvent at ambient temperature and thereby rearranging the 7-acyl group to the 6-position is known (Japanese Patent Application Kokai (Laid-Open) No. 63-10783), for example.
However, the process mentioned above is unsuitable for large scale synthesis in that it yields 7-deacetylforskolin as a by-product formed by hydrolysis of starting compound, which lowers the yield of main product and complicates the procedure o purification because the by-product can be removed only by chromatography.